Various techniques have been proposed for protecting against unauthorized access to secret or private information stored in data storage devices. The two most prevalent techniques can be broadly characterized as hardware write protection and software write protection. Hardware write protection generally involves the use of a write protection clock. Software write protection is generally implemented by means of a directory which includes a list of the files to which access is not permitted without special permission, and the files which are permitted to be altered or updated.
A primary shortcoming of the presently available data protection schemes is that they do not effectively prevent an unauthorized person from reading out the secret files. For example, although most computers are programmed to permit access only to persons who input a valid password, this security measure is, in reality, too easily defeated. Other systems only provide a warning or cautionary message when unauthorized accesses are made.
Based on the above, it can be appreciated that there presently exists a need for a data storage device which eliminates the above-described drawbacks and shortcomings of the presently available data storage devices. The present invention fulfills this need.